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View Full Version : [Help Needed] Did I just screw up my 1C's???


nspindel
06-01-2009, 10:35 PM
I opened them up tonight to swap out the inductors and install the Erse's that I pulled from the 2B's I'm selling.

Just out of curiousity, I put my multimeter across the speaker posts. The right channel is measuring 4 ohms, but the left channel is reading 8.4 ohms. Not quite sure what I could have screwed up here, any ideas???

And no, I didn't check the metering before I pulled the stock inductors, so I have no idea if it was like this before....
nspindel
06-01-2009, 11:40 PM
Found it, snapped one of the leads off the XO out to the inductor. Easily fixed...
thsmith
06-01-2009, 11:48 PM
Found it, snapped one of the leads off the XO out to the inductor. Easily fixed...

What a relief !

Glad you found it and it is repairable.
nspindel
06-01-2009, 11:51 PM
Thanks. Btw, got the t-nuts today. Thanks again!!!
F1nut
06-02-2009, 12:04 AM
That kind of stuff will give you gray hair.
nspindel
06-02-2009, 12:18 AM
4 ohms, good to go!
nspindel
06-02-2009, 12:18 AM
That kind of stuff will give you gray hair.

Already have enough:p
nspindel
06-02-2009, 12:21 AM
Never realized these speakers were 4 ohms, I always thought they were 6. The Krell I'm getting next week pushes 500w into 4 ohms. Yeah, that oughtta suffice...
fbm211
06-02-2009, 01:40 AM
I thought I had 6 ohm 2bs about a year ago untill I got a MM.I was pleased to find mine are 4 ohms.Is that rare to have 4ohm 2Bs?
nspindel
06-02-2009, 08:58 AM
The 2b's I'm about to sell to Big Dawg measure 4. The 1C's are actually measuring 3.6, that's probably because the resistance of the Erse inductor is lower (the whole point of using it...)
Face
06-02-2009, 01:06 PM
The DCR across your binding posts is not the speaker's true impedance.

A speaker that measures 3.2-3.6 is more than likely 4ohms nominal, 6-7 is closer to 8ohms, etc... The only way to know for sure is to use a tool such as Woofer Tester 2 or 3.
nspindel
06-02-2009, 01:10 PM
ah, never realized that. well, the DCR was certainly good enough to find the broken lead in the XO, that's all I really care about :D
jon s
06-02-2009, 02:15 PM
Question... If I were to change an iron core inductor on a crossover with an air core inductor with the same value in millihenries but the impedance is different, will that make a big difference?
F1nut
06-02-2009, 02:20 PM
Yes, I would think so.
Face
06-02-2009, 02:20 PM
Do you mean different DCR's? I would look for an air core with a DCR as close to the original as possible, otherwise you might throw the speaker's balance off.
nspindel
06-02-2009, 02:21 PM
Presumably the iron core has a lower impedance, no? I just did exactly the opposite for this reason. The lower impedance definitely gives the bass a bit of extra oomph.
nspindel
06-02-2009, 02:22 PM
Anyone remember where that thread was where we talked about this? IIRC, Matthew Polk himself chimed in. I never subscribed to it....
nspindel
06-02-2009, 02:27 PM
Ah, here it is, F1 got the quote from MP:

http://www.polkaudio.com/forums/showthread.php?t=66983

jon s, give that a read...
nspindel
06-02-2009, 02:36 PM
You don't see posts like #21 in that thread every day...

As for me, I've been quite happy with the Erse inductors, but that's probably because my speakers are in a small room so I don't push them very hard. In a larger room I might see some of the saturation issues described, but at the lower levels where I listen the Erse certainly is very pleasing.
nspindel
06-02-2009, 02:39 PM
Also, with respect to the saturation concerns, I just looked up the Erse on PartsExpress. While it doesn't give explicit specs, it does say this:

"Finally, a sonically superior magnetic core coil! The Super Q line features a specially shaped core that allows for optimal magnetic performance and increases the coil's effective permeability. The result is extremely low DC resistance, reduced distortion and very high saturation levels. The coils are encapsulated in a plastic housing, which eliminates any magneto striction distortion and makes mounting a breeze. The 500 watt power rating makes these coils perfect for high power prosound applications."
GV#27
06-02-2009, 10:14 PM
The DCR across your binding posts is not the speaker's true impedance.

Correct it's the just the measure of pure resistance to DC.Impedance is the measure of resistance to AC plus any inductance ,capacitance.


Question... If I were to change an iron core inductor on a crossover with an air core inductor with the same value in millihenries but the impedance is different, will that make a big difference?If the DCR values are reasonably close you should be fine.The air core has the potential to improve sound quality if the iron core was prone to saturation.